低压气井修井注气吞吐复产气液两相渗流规律

The Law of Gas-Liquid Two-Phase Seepage for Workover Gas Injection Huff and Puff Production Recovery in Low-Pressure Gas Wells

在低压气井修井复产所采用的注气吞吐工艺中,准确预测气、液两相渗流规律是高效复产的关键环节。以龙会山—铁山区块气井开发现状及复产情况为基础,选取飞仙关组3段孔隙型、孔隙-裂缝型两类储层短岩心,开展岩心驱替实验,分析气、液两相渗流规律。将实验数据进行归一化处理,形成了气、液相对渗透率曲线标准图版;针对孔隙-裂缝型储层的渗流特点建立假设,在考虑非均质性的情况下提出气、液两相相对渗透率曲线校正方法并对相应图版进行校正。校正后的裂缝型碳酸盐岩储层气液两相渗流曲线能更真实地反应气液两相渗流规律,孔隙-裂缝型储层中的束缚水饱和度比校正前图版更小,实际共渗范围更大,驱替效率更高。研究工作可为孔隙-裂缝型碳酸盐岩气藏开发提供理论参考。

For the gas injection huff and puff process used for the workover and production recovery in low-pressure gas wells,accurate prediction of the law of gas-liquid two-phase seepage is the key to efficient production recovery.Based on the development status and production recovery of gas wells in the Longhuishan-Tieshan block,the pore type and pore-fracture type reservoir short cores from the Member 3 of the Feixianguan Formation were selected to conduct core flooding experiments and study the law of gas-liquid two-phase seepage.The experimental data were normalized to form a standard chart of the gas-liquid two-phase seepage curve.A hypothesis was established for the seepage characteristics of pore-fracture reservoirs,and a correction method for the gas-liquid two-phase seepage curve was proposed by considering anisotropy,and corrections were made to the corresponding chart.The corrected gas-liquid two phase seepage curve of fractured carbonate reservoirs better mirrors the gas-liquid two-phase seepage pattern.The saturation of the bound water in pore-fractured reservoirs is lower than that in the pre-corrected curve,with a larger actual co-infiltration range and higher displacement efficiency.This research provides the theoretical basis for the development of pore-fracture carbonate gas reser-voirs.